Home sharing problem

Hey ASC!

Here the problem:I am turning on Home Sharing on my iTunes on my iMac 27" ..I put my email and password! And its turned on!

Then I am turning on Home Sharing on my iPhone 4S ,again I put my email and password and that is turned on too!

Then I used to choose the Remote App on my iPhone to change the music on my iMac remotely when I was away and everything it was alright!

But I don't know what's wrong lately I can't connect those devices and I can't remotely control my iTunes on my iMac!What is the problem?

I hope you understand .. Sorry for the bad english .. It's not my native language!

Thanks!